Watford manager Marco Silva will take a late decision on the fitness of Andre Carrillo for the visit of Arsenal.
Carrillo, the winger on a season-long loan from Benfica, played for Peru in their 1-1 World Cup qualifier against Colombia on Wednesday night.
Forward Isaac Success has been ruled out for up to eight weeks with a knee injury, while Sebastian Prodl (thigh) is a doubt and Younes Kaboul (hamstring) remains sidelined.
Arsene Wenger, meanwhile, will assess Alexis Sanchez's physical and mental condition shortly before kick off.
Sanchez only arrived back in London on Thursday after missing out on World Cup qualification with Chile but Mesut Ozil and Danny Welbeck are available, having overcome knee and groin injuries respectively.
Shkodran Mustafi suffered a thigh strain over the international break and is set to be out for four to six weeks while Laurent Koscielny (Achilles) and Sead Kolasinac (hip) will be given late fitness tests. Calum Chambers (hip), Francis Coquelin (hamstring) and Santi Cazorla (ankle) are all out.
Watford squad: Gomes, Holebas, Kabasele, Britos, Mariappa, Femenia, Carrillo, Richarlison, Cleverley, Doucoure, Capoue, Gray, Karnezis, Deeney, Wague, Pereyra, Janmaat, Watson.
Arsenal squad: Cech, Ospina, Macey, Koscielny, Mertesacker, Holding, Monreal, Kolasinac, Bellerin, Debuchy, Elneny, Xhaka, Maitland-Niles, Ramsey, Wilshire, Ozil, Walcott, Sanchez, Welbeck, Lacazette, Giroud, Akpom.